package org.openslx.dozmod.gui.window;

import java.awt.Color;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import javax.swing.DefaultComboBoxModel;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;

import org.apache.log4j.Logger;
import org.apache.thrift.TException;
import org.openslx.bwlp.thrift.iface.ImageDetailsRead;
import org.openslx.bwlp.thrift.iface.ImageSummaryRead;
import org.openslx.bwlp.thrift.iface.ImageVersionDetails;
import org.openslx.bwlp.thrift.iface.LecturePermissions;
import org.openslx.bwlp.thrift.iface.LectureRead;
import org.openslx.bwlp.thrift.iface.LectureWrite;
import org.openslx.bwlp.thrift.iface.UserInfo;
import org.openslx.dozmod.gui.Gui;
import org.openslx.dozmod.gui.MainWindow;
import org.openslx.dozmod.gui.helper.DateTimeHelper;
import org.openslx.dozmod.gui.helper.MessageType;
import org.openslx.dozmod.gui.helper.UiFeedback;
import org.openslx.dozmod.gui.window.UserListWindow.UserAddedCallback;
import org.openslx.dozmod.gui.window.layout.LectureDetailsWindowLayout;
import org.openslx.dozmod.permissions.ImagePerms;
import org.openslx.dozmod.permissions.LecturePerms;
import org.openslx.dozmod.thrift.Session;
import org.openslx.dozmod.thrift.ThriftActions;
import org.openslx.dozmod.thrift.ThriftActions.DownloadCallback;
import org.openslx.dozmod.thrift.ThriftActions.LectureMetaCallback;
import org.openslx.dozmod.thrift.ThriftError;
import org.openslx.dozmod.thrift.cache.UserCache;
import org.openslx.dozmod.util.FormatHelper;
import org.openslx.dozmod.util.MapHelper;
import org.openslx.thrifthelper.ThriftManager;

/**
 * Window to display and edit the details of a lecture
 */
@SuppressWarnings("serial")
public class LectureDetailsWindow extends LectureDetailsWindowLayout implements UiFeedback {

	private static final Logger LOGGER = Logger.getLogger(LectureDetailsWindow.class);

	/**
	 * Self-reference
	 */
	private final LectureDetailsWindow me = this;

	/**
	 * Callback interface to refresh lecture list after changing lecture details
	 */
	public interface LectureUpdatedCallback {
		public void updated(boolean success);
	}

	/**
	 * Callback to be called when changing lecture details on the server
	 */
	private LectureUpdatedCallback callback = null;

	/**
	 * Lecture that this window shows the details of
	 */
	private LectureRead lecture = null;

	/**
	 * The custom permissions of the lecture
	 */
	private Map<String, LecturePermissions> customPermissions;

	/**
	 * The original custom permissions as fetched from the server
	 */
	private Map<String, LecturePermissions> originalCustomPermissions;

	/**
	 * The original default permissions as fetched from the server
	 */
	private LecturePermissions originalDefaultPermissions;
	/**
	 * Image, that the lecture is linked to.
	 */
	private ImageDetailsRead image = null;

	private boolean imageLinkChanged = false;

	private boolean metadataChanged = false;

	private boolean permissionsChanged;

	/**
	 * Constructor
	 * 
	 * @param modalParent parent of this popup window
	 */
	public LectureDetailsWindow(Frame modalParent, LectureUpdatedCallback callback) {
		super(modalParent);
		// save callback
		this.callback = callback;

		setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
		addWindowListener(new WindowAdapter() {
			@Override
			public void windowClosing(WindowEvent e) {
				safeClose();
			}
		});

		btnLinkImage.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				ImageSummaryRead newImage = LectureChangeImage.open(me);
				if (newImage != null) {
					try {
						image = ThriftManager.getSatClient().getImageDetails(Session.getSatelliteToken(),
								newImage.imageBaseId);
					} catch (TException e1) {
						LOGGER.error("Failed to retrieve details of new image: ", e1);
						return;
					}
					lecture.imageBaseId = newImage.imageBaseId;
					lecture.imageVersionId = newImage.latestVersionId;
					fillVersionsCombo();
					cboVersions.setEnabled(false);
					chkAutoUpdate.setSelected(true);
					imageLinkChanged = true;
					txtImageName.setText(newImage.getImageName());
					reactToChange();
				}
			}
		});

		btnClose.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				safeClose();
			}
		});
		btnDownloadImage.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				performImageDownload();
			}
		});
		chkAutoUpdate.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				cboVersions.setEnabled(!chkAutoUpdate.isSelected());
			}
		});
		btnChangeOwner.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				UserListWindow.open(me, new UserAddedCallback() {
					@Override
					public void userAdded(UserInfo user, UserListWindow window) {
						window.dispose();
						if (Gui.showMessageBox(me, "Sind Sie sicher, dass sie die Besitzerrechte an "
								+ "einen anderen Account übertragen wollen?", MessageType.QUESTION_YESNO,
								LOGGER, null))
							setLectureOwner(user);
					}
				}, "Besitzer festlegen", lecture.ownerId);
			}
		});
		btnPermissions.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent arg0) {
				// NOTE once the following window is closed, customPermissions and lecture.defaultPermissions
				// objects will contain the changes the user did. We will later only compare these with
				// the original values as saved in originalCustomPermissions and originalDefaultPermissions
				LecturePermissionWindow.open(me, customPermissions, lecture.defaultPermissions,
						lecture.ownerId);
				reactToChange();
			}
		});
		btnSaveChanges.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				saveChanges();
			}
		});

		// final step, add listeners to react to change
		final DocumentListener docListener = new DocumentListener() {
			@Override
			public void removeUpdate(DocumentEvent e) {
				changedUpdate(e);
			}

			@Override
			public void insertUpdate(DocumentEvent e) {
				changedUpdate(e);
			}

			@Override
			public void changedUpdate(DocumentEvent e) {
				reactToChange();
			}
		};
		txtTitle.getDocument().addDocumentListener(docListener);
		txtDescription.getDocument().addDocumentListener(docListener);

		// Comboboxes
		final ItemListener comboItemListener = new ItemListener() {
			@Override
			public void itemStateChanged(ItemEvent e) {
				if (e.getStateChange() == ItemEvent.SELECTED) {
					reactToChange();
				}
			}
		};
		cboVersions.addItemListener(comboItemListener);

		// Listener to detect changes in checkboxes
		final ActionListener actionListener = new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				reactToChange();
			}
		};
		ChangeListener changeListener = new ChangeListener() {
			@Override
			public void stateChanged(ChangeEvent e) {
				reactToChange();
			}
		};
		chkAutoUpdate.addActionListener(actionListener);
		chkIsExam.addActionListener(actionListener);
		chkHasInternetAccess.addActionListener(actionListener);
		chkIsActive.addActionListener(actionListener);
		startDate.addActionListener(actionListener);
		endDate.addActionListener(actionListener);
		startTime.addChangeListener(changeListener);
		endTime.addChangeListener(changeListener);

		// save default color of date/time stuff to reset the background later
		dateTimeTextColor = startDate.getForeground();
		// disable save button
		btnSaveChanges.setEnabled(false);
		// wait for the image to be loaded before (potentially) enabling fields
		makeEditable(false);
	}

	/**
	 * Sets the lecture to show the details of by setting the 'lecture' and
	 * 'image'
	 * members to its metadata. This method will fetch the information from the
	 * sat
	 * 
	 * @param lectureId the id of the lecture to be displayed
	 */
	public void setLecture(final String lectureId) {
		ThriftActions.getLectureAndImageDetails(JOptionPane.getFrameForComponent(me), lectureId,
				new LectureMetaCallback() {
					@Override
					public void fetchedLectureAndImageDetails(LectureRead lectureDetails,
							ImageDetailsRead imageDetails) {
						synchronized (me) {
							lecture = lectureDetails;
							image = imageDetails;
							if (lecture != null) {
								customPermissions = ThriftActions.getLecturePermissions(
										JOptionPane.getFrameForComponent(me), lecture.lectureId);
							}
						}
						fillDetails();
					}
				});
	}

	/**
	 * callback function when we received the lecture's details from the server
	 */
	private void fillDetails() {
		if (lecture == null) {
			txtTitle.setText("-");
			makeEditable(false);
			return;
		}
		if (image == null) {
			txtImageName.setText("-");
		} else {
			txtImageName.setText(image.getImageName());
		}
		// remember default permissions
		if (lecture.defaultPermissions != null) {
			originalDefaultPermissions = new LecturePermissions(lecture.defaultPermissions);
		}
		// remember custom permissions
		if (customPermissions != null) {
			// need a deep copy of the permission map to be able to check for changes after ImageCustomPermissionWindow
			if (originalCustomPermissions == null)
				originalCustomPermissions = new HashMap<String, LecturePermissions>();
			else
				originalCustomPermissions.clear();
			// fill it
			for (Entry<String, LecturePermissions> entry : customPermissions.entrySet()) {
				originalCustomPermissions.put(entry.getKey(), new LecturePermissions(entry.getValue()));
			}
		}
		txtTitle.setText(lecture.getLectureName());
		txtDescription.setText(lecture.getDescription());
		lblOwner.setUser(UserCache.find(lecture.getOwnerId()));
		lblUpdater.setUser(UserCache.find(lecture.getUpdaterId()));
		lblCreateTime.setText(FormatHelper.longDate(lecture.getCreateTime()));
		lblUpdateTime.setText(FormatHelper.longDate(lecture.getUpdateTime()));
		lblStartTime.setText(FormatHelper.longDate(lecture.getStartTime()));
		lblEndTime.setText(FormatHelper.longDate(lecture.getEndTime()));
		txtId.setText(lecture.getLectureId());

		chkIsActive.setSelected(lecture.isEnabled);
		chkHasInternetAccess.setSelected(lecture.hasInternetAccess);
		chkIsExam.setSelected(lecture.isExam);
		chkAutoUpdate.setSelected(lecture.autoUpdate);
		cboVersions.setEnabled(!lecture.autoUpdate);

		lblUseCount.setText(Integer.toString(lecture.useCount));

		fillVersionsCombo();

		Calendar startCal = Calendar.getInstance();
		startCal.setTime(new Date(lecture.getStartTime() * 1000l));
		startDate.getModel().setDate(startCal.get(Calendar.YEAR), startCal.get(Calendar.MONTH),
				startCal.get(Calendar.DATE));
		startTime.getModel().setValue(startCal.getTime());

		Calendar endCal = Calendar.getInstance();
		endCal.setTime(new Date(lecture.getEndTime() * 1000l));
		endDate.getModel().setDate(endCal.get(Calendar.YEAR), endCal.get(Calendar.MONTH),
				endCal.get(Calendar.DATE));
		endTime.getModel().setValue(endCal.getTime());

		makeEditable(true);
		setVisible(true);
	}

	/**
	 * Helper to fill the combobox with the versions of the image. The list will
	 * be sorted by creation timestamp
	 */
	private void fillVersionsCombo() {
		List<ImageVersionDetails> versions;
		if (image == null) {
			versions = new ArrayList<>(0);
		} else {
			versions = image.getVersions();
		}
		// version combo
		for (Iterator<ImageVersionDetails> it = versions.iterator(); it.hasNext();) {
			ImageVersionDetails version = it.next();
			if (!version.isValid && !lecture.imageVersionId.equals(version.versionId)) {
				it.remove();
			}
		}

		// sort versions by createtime
		Collections.sort(versions, new Comparator<ImageVersionDetails>() {
			public int compare(ImageVersionDetails o1, ImageVersionDetails o2) {
				return -Long.compare(o1.getCreateTime(), o2.getCreateTime());
			}
		});

		cboVersions.setModel(new DefaultComboBoxModel<ImageVersionDetails>(
				versions.toArray(new ImageVersionDetails[versions.size()])));
		cboVersions.setSelectedItem(new ImageVersionDetails(lecture.getImageVersionId(), 0, 0, 0, null, true,
				true, true, null));
	}

	/**
	 * Sets the lecture's owner to the given user
	 * 
	 * @param user UserInfo representation of the new owner
	 */
	private void setLectureOwner(final UserInfo user) {
		if (!ThriftActions.setLectureOwner(JOptionPane.getFrameForComponent(this), lecture.getLectureId(),
				user)) {
			return;
		}
		// success
		Gui.showMessageBox(me, "Besitzrechte übertragen an " + FormatHelper.userName(user), MessageType.INFO,
				null, null);
		makeEditable(false);
		String lectureId = lecture.getLectureId();
		synchronized (me) {
			image = null;
			lecture = null;
		}
		setLecture(lectureId);
	}

	/**
	 * Triggers the download of the currently used image version of the lecture
	 */
	private void performImageDownload() {
		if (image == null) {
			Gui.showMessageBox(this, "Image ungültig.", MessageType.ERROR, null, null);
			return;
		}
		btnDownloadImage.setEnabled(false);
		long versionSize = 0;
		for (ImageVersionDetails version : image.versions) {
			if (version.versionId.equals(lecture.imageVersionId)) {
				if (!version.isValid) {
					Gui.showMessageBox(this, "Ungültiges Image gewählt", MessageType.ERROR, null, null);
					return;
				}
				versionSize = version.fileSize;
				break;
			}
		}
		if (versionSize == 0) {
			Gui.showMessageBox(this, "Fehler bei der Abfrage der Größe des Images.", MessageType.ERROR, null,
					null);
			return;
		}
		ThriftActions.initDownload(JOptionPane.getFrameForComponent(this), lecture.imageVersionId,
				image.imageName, image.virtId, image.osId, versionSize, new DownloadCallback() {
					@Override
					public void downloadInitialized(boolean success) {
						if (!success) {
							Gui.asyncExec(new Runnable() {
								@Override
								public void run() {
									btnDownloadImage.setEnabled(true);
								}
							});
						}
					}
				});
	}

	/**
	 * Push the changes of the image details to the satellite
	 */
	private void saveChanges() {
		boolean saved = saveChangesInternal();
		callback.updated(saved);
		if (saved)
			dispose();
		else
			btnSaveChanges.setEnabled(true);
	}

	private boolean saveChangesInternal() {
		// check, whether autoupdate is selected and choose version accordingly
		if (image != null) {
			lecture.imageVersionId = chkAutoUpdate.isSelected() ? image.latestVersionId
					: cboVersions.getItemAt(cboVersions.getSelectedIndex()).versionId;
		}
		// now check if we need to push a new LectureWrite
		if (metadataChanged) {
			// first build the LectureWrite from the GUI fields
			final LectureWrite metadata = new LectureWrite(txtTitle.getText(), txtDescription.getText(),
					lecture.getImageVersionId(), chkAutoUpdate.isSelected(), chkIsActive.isSelected(),
					DateTimeHelper.getDateFrom(startDate, startTime).getTime() / 1000L,
					DateTimeHelper.getDateFrom(endDate, endTime).getTime() / 1000L, null, null,
					chkIsExam.isSelected(), chkHasInternetAccess.isSelected(),
					lecture.getDefaultPermissions());
			// now trigger the actual action 
			try {
				ThriftManager.getSatClient().updateLecture(Session.getSatelliteToken(),
						lecture.getLectureId(), metadata);
				metadataChanged = false;
				LOGGER.info("Successfully save new metadata");
			} catch (TException e) {
				ThriftError.showMessage(JOptionPane.getFrameForComponent(this), LOGGER, e,
						"Fehler beim Updaten der Veranstaltung!");
				callback.updated(false);
				return false;
			}
		}
		if (permissionsChanged) {
			try {
				ThriftManager.getSatClient().writeLecturePermissions(Session.getSatelliteToken(),
						lecture.lectureId, customPermissions);
				permissionsChanged = false;
				LOGGER.info("Successfully save new permissions");
			} catch (TException e) {
				ThriftError.showMessage(JOptionPane.getFrameForComponent(this), LOGGER, e,
						"Fehler beim Übertragen der Berechtigungen!");
				callback.updated(true);
				return false;
			}
		}
		return true;
	}

	/**
	 * Checks if the given start and end date represent a valid time period.
	 * This is the case, if start < end and if current time < end
	 * 
	 * @param start date of the period to check
	 * @param end date of the period to check
	 * @param feedback true if the user should be shown feedback, false
	 *            otherwise
	 * @return true if the period is valid, false otherwise
	 */
	private boolean isPeriodValid(final Date start, final Date end, boolean feedback) {
		if (start == null || end == null)
			return false;
		// analyse time stuff to see if its valid
		if (start.after(end)) {
			startDate.setForeground(Color.red);
			if (feedback)
				Gui.showMessageBox(me, "Start der Veranstaltung ist nach dem Enddatum!", MessageType.ERROR,
						LOGGER, null);
		} else {
			startDate.setForeground(dateTimeTextColor);
			final Date now = new Date();
			if (now.after(end)) {
				if (feedback)
					Gui.showMessageBox(me, "Enddatum liegt in der Vergangenheit!", MessageType.ERROR, LOGGER,
							null);
				endDate.setForeground(Color.red);
			} else {
				endDate.setForeground(dateTimeTextColor);
				return true;
			}
		}
		return false;
	}

	/**
	 * Check whether the date has been changed
	 * 
	 * @return true if it has changed, false otherwise
	 */
	private boolean dateHasChanged() {
		return (DateTimeHelper.getDateFrom(startDate, startTime).getTime() / 1000L) != lecture.getStartTime()
				|| (DateTimeHelper.getDateFrom(endDate, endTime).getTime() / 1000L) != lecture.getEndTime();
	}

	/**
	 * Checks whether the user changed any fields of the image details and
	 * enables the save button if so.
	 */
	private void reactToChange() {
		// check details fields
		metadataChanged = reactToChangeInternal();
		permissionsChanged = MapHelper.hasChanged(originalCustomPermissions, customPermissions);
		btnSaveChanges.setEnabled(metadataChanged || permissionsChanged);
	}

	/**
	 * Checks whether the user changed any fields of the image details and
	 * enables the save button if so.
	 */
	private boolean reactToChangeInternal() {
		if (lecture == null)
			return false;

		boolean changed = false;
		// mandatory fields checks
		if (txtTitle.getText().isEmpty()) {
			lblError.setText("Kein Imagename!");
			return false;
		}
		if (txtDescription.getText().isEmpty()) {
			lblError.setText("Keine Beschreibung!");
			return false;
		}
		// version checkbox changed?
		ImageVersionDetails currentVersion = cboVersions.getItemAt(cboVersions.getSelectedIndex());
		if (currentVersion == null) {
			lblError.setText("Keine Version ausgewählt!");
			return false;
		}
		// Date stuff
		Date start = DateTimeHelper.getDateFrom(startDate, startTime);
		Date end = DateTimeHelper.getDateFrom(endDate, endTime);
		if (!isPeriodValid(start, end, false) && dateHasChanged()) {
			lblError.setText("Ungültiger Zeitraum!");
			return false;
		}

		// done with mandatory checks, remove error message
		lblError.setText(null);

		// check for changes in all fields
		changed = !txtTitle.getText().equals(lecture.getLectureName())
				|| !txtDescription.getText().equals(lecture.getDescription())
				|| !currentVersion.getVersionId().equals(lecture.getImageVersionId())
				|| (DateTimeHelper.getDateFrom(startDate, startTime).getTime() / 1000L) != lecture.getStartTime()
				|| (DateTimeHelper.getDateFrom(endDate, endTime).getTime() / 1000L) != lecture.getEndTime()
				|| chkAutoUpdate.isSelected() != lecture.autoUpdate
				|| chkIsExam.isSelected() != lecture.isExam
				|| chkHasInternetAccess.isSelected() != lecture.hasInternetAccess
				|| chkIsActive.isSelected() != lecture.isEnabled
				|| !lecture.defaultPermissions.equals(originalDefaultPermissions) || imageLinkChanged;

		return changed;
	}

	/**
	 * Enables/disables the editable fields based on 'editable'
	 * 
	 * @param editable true to make fields editable, false otherwise.
	 */
	private void makeEditable(boolean editable) {
		editable = editable && (LecturePerms.canEdit(lecture) || LecturePerms.canAdmin(lecture));
		txtTitle.setEditable(editable);
		txtDescription.setEditable(editable);
		btnLinkImage.setEnabled(editable);
		chkIsExam.setEnabled(editable);
		chkHasInternetAccess.setEnabled(editable);
		chkIsActive.setEnabled(editable);
		chkAutoUpdate.setEnabled(editable);
		cboVersions.setEnabled(editable && !lecture.autoUpdate && image != null);
		btnChangeOwner.setEnabled(editable && LecturePerms.canAdmin(lecture));
		btnPermissions.setEnabled(editable && LecturePerms.canAdmin(lecture));
		startDate.setEnabled(editable);
		startTime.setEnabled(editable);
		endDate.setEnabled(editable);
		endTime.setEnabled(editable);
		btnDownloadImage.setEnabled(ImagePerms.canDownload(image));
	}

	/**
	 * Opens a new LectureDetailsWindow showing the details of the
	 * lecture with ID = lectureId
	 * 
	 * @param modalParent parent of this window
	 * @param lectureId id of the lecture to set the details of
	 */
	public static void open(Frame modalParent, String lectureId, LectureUpdatedCallback callback) {
		LectureDetailsWindow win = new LectureDetailsWindow(modalParent, callback);
		win.setLecture(lectureId);
		win.setVisible(true);
	}

	@SuppressWarnings("deprecation")
	@Override
	public void show() {
		if (!isVisible()) {
			pack();
			MainWindow.centerShell(this);
		}
		super.show();
	}

	/* *******************************************************************************	
	 * 
	 *                        UIFeedback implementation
	 *
	 ********************************************************************************/
	@Override
	public boolean wantConfirmQuit() {
		return metadataChanged || permissionsChanged;
	}

	@Override
	public void escapePressed() {
		// Also ask if applicable
		safeClose();
	}

	/*
	 * Safe close helper: checks if we have unsaved work and prompt the user for
	 * confirmation if so
	 */
	private void safeClose() {
		if ((metadataChanged || permissionsChanged)
				&& !Gui.showMessageBox(me, "Änderungen werden verworfen, wollen Sie wirklich schließen?",
						MessageType.QUESTION_YESNO, null, null))
			return;
		dispose();
	}
}